... The Wide Field Spectral Imager ( WISPI ) seen here in the Roll Roof Facility provides visible and near-infrared spectra of the sky across 4 degree fields. ... A computer controlled mounting automates the acquisition of 2-D rastered spectral images. ... Light from the sky enters the large 400mm lens at top center, is imaged on the slit, collimated by the smaller 180 mm lens, and diffracted by the grating at the bottom toward the 200mm lens and CCD camera on the right. ... Camera - 200mm f/2 Nikor ED ...